A world of applications

Find out how IRMS is applied across many research themes

Our customers use our instruments to do some amazing research. Across a diverse array of applications, they apply stable isotope ratio mass spectrometry (IRMS) analysis to understand the micro and macro cycling of the light bio elements carbon, oxygen, nitrogen, hydrogen and sulfur via complex chemical, physical and biological processes.

We take a great interest in our customers research and we are proud that they further the collective understanding using our array of instrumentation. With over 600 IRMS instruments being used around the world, there is a vast amount of published literature available but here you will find just some of those citations that have recently been produced using our IRMS systems.

If you would like to discuss how IRMS might be able to help your research and would like to talk to one of our technical specialists, or if you have used our IRMS instruments in one of your publications which is not in our database and like to add it, then please feel free to contact us.

Spatial and temporal variations of gas geochemistry at Mt. Ontake, JapanJournal of Volcanology and Geothermal Research (2016)

This report describes spatial and temporal variations of helium, carbon, and nitrogen isotopes measured in CO2-rich bubbling gases from natural springs associated with Mt. Ontake (central Honshu, Japan) from November 1981 through September 2015. During the entire period, the 3He/4He ratio decreased concomitantly with increasing distance of the sampling site from the central cone. In contrast, the CO2/3He ratios and the δ13C values of CO2 increased with distance. These spatial trends became more pronounced after the September 27, 2014 Ontake eruption, suggesting reactivation of the volcano plumbing system with enhanced emission of magmatic volatiles, although the spatial trend of nitrogen isotopes disappeared. The 3He/4He ratios of the most proximal site to the central cone remained constant until 2000, apparently increasing from June 2003 through October 2014. They became constant soon after the eruption until September 2015. The ten-year 3He enhancement might have been a precursor of the 2014 Ontake eruption. In contrast, δ13C values of CO2 at the same site remained constant through this period. The lack of δ13C anomaly might be attributable to 1) negligibly small amounts of magmatic CO2 introduced into the source of hot springs compared to ambient CO2 in the air-saturated aquifer, or 2) close resemblance of the carbon signature of magmatic CO2 to that of ambient CO2. Therefore its addition cannot change the overall δ13C value of the sampled hot springs. At distal sampling sites, no measurable change of helium, carbon, or nitrogen isotopes was observed in relation to the 2014 Ontake eruption, suggesting that the effect of this eruption on the Ontake hydrothermal system was geographically localized.

Seasonal migration and natal dispersal represent the major large-scale movements in the lives of animals. Individuals that are relatively prone to movement and exploration might thus be more likely to disperse and also to migrate farther. Such movement might be either negatively associated with parasitic infection (if infection prevents hosts from successful long-distance migration) or positively associated (e.g. if longer-distance migrants encounter more abundant or more diverse parasites). We examined whether natal dispersal tendency predicts seasonal migration distance in song sparrows (Melospiza melodia) and whether migration distance predicts infection with bloodborne parasites upon arrival at the breeding grounds. Migration distance, inferred from stable hydrogen isotope analysis (δ2H) of winter-grown tissue, was repeatable (repeatability = 0.41) over years. Birds that were more likely to have immigrated from outside the breeding grounds, as inferred from genetic assignment tests, also overwintered farther south, as inferred from stable isotope analysis. The finding that individuals more prone to movement in the context of natal dispersal also tended to travel farther, on average, in the context of seasonal migration suggests consistent individual variation in large-scale movements across these two contexts. Although statistically significant, this effect was modest in scope and subtle relative to sex differences in inferred migration distance. Among after-second-year individuals, but not yearlings, longer-distance migrants were more likely, on average, to be infected with bloodborne parasites. Individual variation in propensity to long-distance movement may interact with age-related variation in exposure or susceptibility to parasites, to shape the role of animal migration in transporting infectious disease.

Stable isotope analyses for shortfin mako (Isums oxyrinchus) and blue sharks (Prionace glauca) were conducted to assess their trophic position in two periods of time (before 1980 and after 2000) in the Southeastern Pacific waters (SEP). Both sharks showed that their trophic position decreased over time (P < 0.05). Many factors could be involved in this change such as dietary shifts, prey availability, or indirect fishing effects in SEP waters.

Dorothee M. Kottmeier, Sebastian D. Rokitta, Björn Rost

Recent ocean acidification (OA) studies revealed that seawater [H1] rather than [CO2] or [HCO2 3 ] regulate short-term responses in carbon fluxes of Emiliania huxleyi. Here, we investigated whether acclimation to altered carbonate chemistry modulates this regulation pattern and how the carbon supply for calcification is affected by carbonate chemistry. We acclimated E. huxleyi to present-day (ambient [CO2], [HCO2 3 ], and pH) and OA conditions (high [CO2], ambient [HCO2 3 ], low pH). To differentiate between the CO2 and pH/H1 effects, we also acclimated cells to carbonation (high [CO2] and [HCO2 3 ], ambient pH) and acidification (ambient [CO2], low [HCO2 3 ], and pH). Under these conditions, growth, production of particulate inorganic and organic carbon, as well as carbon and oxygen fluxes were measured. Under carbonation, photosynthesis and calcification were stimulated due to additional HCO2 3 uptake, whereas growth was unaffected. Such stimulatory effects are not apparent after short-term carbonation, indicating that cells adjusted their carbon acquisition during acclimation. Being driven by [HCO2 3 ], these regulations can, however, not explain typical OA effects. Under acidi- fication and OA, photosynthesis stayed constant, whereas calcification and growth decreased. Similar to the short-term responses toward high [H1], CO2 uptake significantly increased, but HCO2 3 uptake decreased. This antagonistic regulation in CO2 and HCO2 3 uptake can explain why photosynthesis, being able to use CO2 and HCO2 3 , often benefits from OA, whereas calcification, being mostly dependent on HCO2 3 , often decreases. We identified H1 as prime driver of coccolithophores’ acclimation responses toward OA. Acidified conditions seem to put metabolic burdens on the cells that result in decreased growth.

Stable isotope on the evaluation of water quality in the presence of WWTPs in riversEnvironmental Science and Pollution Research (2016)

We investigated the distribution of nitrogen compounds in Han River as well as two tributaries of Tancheon and Jungrangcheon. Particularly, we observed the significant releases of NH4 +-N from effluent of wastewater treatment plants (WWTPs) in two tributaries that has resulted in the increases of ammonium nitrogen (NH4 +-N) in Han River as well as in Tancheon and Jungrangcheon. Due to the increases of NH4 +-N in two tributaries, the larger distribution of δ15N-NH4 + was observed than those of δ15N-NO3 − in downstream. We calculated the contribution rate of ammonium nitrogen and nitrate nitrogen from effluent to downstream according to the results of stable isotope. The contribution rates of δ15N-NH4 + from effluent to downstream were significant that ranged between 53 and 100 % in Tancheon and between 27 and 100 % in Jungrangcheon. While the contribution of δ15N-NO3 − was not significant in Tancheon, it was occasionally observed in Jungrangcheon. These results demonstrated that WWTPs are the major sources of NH4 +-N in two tributaries, which caused the distinguishable stable isotope of δ15N-NH4 +. Therefore, the stable isotope of δ15N-NH4 + could be a useful parameter or tracer for the evaluation of NH4-N released from WWTPs in rivers.

δ15N of annual (Ulva sp., Porphyra sp.) and perennial intertidal seaweed species (Chondrus crispus, Fucus sp.) collected on 17 sampling points along the French coast of the English Channel in 2012 and 2013 were assessed on their suitability as bioindicators of N pollution in coastal areas. A sine function applied for δ15N time series data showed for all the species the same seasonal trend with lowest δ15N values in April and highest in summer but with no significant interspecific differences of amplitude (α) and phase angle (ϕ). This model provides a useful tool for monitoring the inter-annual changes of N pollution. An interspecific variability of δ15N values was observed, probably due to their tolerance to emersion. An in vitro study for comparing the kinetic acquisition of the isotopic signal and N uptake mechanisms of each species underlined the influence of algal physiology on the δ15N interspecific variability.

Tags: nitrogen , ocea , poll , elem

Peat porewaters have contrasting geochemical fingerprints for groundwater recharge and discharge due to matrix diffusion in a large, northern bog-fen complexJournal of Hydrology (2016)

Although northern peatlands represent a globally significant reservoir for carbon, considerable uncertainty exists concerning solute transport systems within large (>1000 km2) peat deposits. We therefore delineated geochemical gradients linked to groundwater recharge and discharge along a 6 km transect within the 1200 km2 Red Lake Peatland of northwestern Minnesota. We used ratios of Ca/Mg and 87Sr/86Sr to distinguish discharge of calcareous groundwater (∼1.4 and 0.7155, respectively) to the peatland from the mineral substratum along a topographic gradient from a bog crest downslope to an internal fen water track and bog islands. In contrast, the stable isotopes of the porewaters (δ18O from -12.8 ‰ to -7.8 ‰) show that the active pore-spaces in these peat profiles has been flushed by recharge from the near-surface peat. We hypothesize that back-diffusion of groundwater-derived solutes from the peat matrix to active pore-spaces has allowed the geochemical signal from paleo-hydrogeologic discharge to persist into the current regime of dilute recharge. This effect has not been observed previously on the landform-scale and has important implications for carbon cycling in peatlands.

Tags: hydrogen , oxygen , soil , gashead

Trophic interactions among pelagic sharks and large predatory teleosts in the northeast central PacificJournal of Experimental Marine Biology and Ecology (2016)

Yunkai Li, Yuying Zhang, Xiaojie Dai

Sharks are considered to play important roles in structuring marine ecosystems, consequently understanding their trophic ecology and interactions with other marine predators is required. In the central Pacific Ocean, whether the trophic roles of pelagic sharks are complementary or redundant to large teleost predators remains unclear. In this study, stable carbon and nitrogen isotope analysis were used to examine the isotopic niche overlap of eight pelagic shark species and six pelagic teleost predators, including tuna and billfish. Large intra-specific variation and minimal inter-specific variation in both δ15N and δ13C values were observed among sharks and teleosts. Moreover, there was a high degree of trophic overlap among pelagic shark and teleost species, with the exception of the blue shark, the δ13C values of which indicated a much longer foraging time in the purely pelagic waters. Moreover, although the stable isotopic data suggested that the pelagic sharks in the study area share similar prey and habitats with other pelagic predators, such as tuna and billfish, blue sharks and shortfin mako sharks did not show isotopic overlap with these predators. These data highlight the diverse roles among pelagic sharks, supporting previous findings that this species complex is not trophically redundant; but further studies on the diet and fine-scale habitat used are required to verify this hypothesis.

Tags: carbon , nitrogen , ecol , elem

High-throughput method for simultaneous quantification of N, C and S stable isotopes and contents in organics and soilsRapid Communications in Mass Spectrometry (2016)

Rationale Information about the sulfur stable isotope composition (δ34S value) of organic materials and sediments, in addition to their nitrogen (δ15N value) and carbon (δ13C value) stable isotope compositions, can provide insights into mechanisms and processes in different areas of biological and geological research. The quantification of δ34S values has traditionally required an additional and often more difficult analytical procedure than NC dual analysis. Here, we report on the development of a high-throughput method that simultaneously measures the elemental and isotopic compositions of N, C and S in a single sample, and over a wide range of sample sizes and C/N and C/S ratios. Methods We tested a commercially available CHNOS elemental analyzer in line with an isotope ratio mass spectrometer for the simultaneous quantification of N, C and S stable isotope ratios and contents, and modified the elemental analyzer in order to overcome the interference of 18O in δ34S values, to minimize any water condensation that could also influence S memory, and to achieve the complete reduction of nitrogen oxides to N2 gas for accurate measurement of δ15N values. A selection of organic materials and soils was analyzed with a ratio of 1:1.4 standards to unknowns per run. Results The modifications allowed high quality measurements for N, C and S isotope ratios simultaneously (1 SD of ±0.13‰ for δ15N value, ±0.12‰ for δ13C value, and ±0.4‰ for δ34S value), with high throughput (>75 unknowns per run) and over a wide range of element amount per capsule (25 to 500 μg N, 200–4000 μg C, and 8–120 μg S). Conclusions This method is suitable for widespread use and can significantly enhance the application of δ34S measurements in a broad range of soils and organic samples in ecological and biogeochemical research

Kinetic commitment in the catalysis of glutamine synthesis by GS1 from Arabidopsis using 14N/15N and solvent isotope effectsPlant Physiology and Biochemistry (2016)

Glutamine synthetase (GS, EC 6.3.1.2) catalyzes the production of glutamine from glutamate, ammonium and ATP. Although being essential in plants for N assimilation and recycling, kinetic commitments and transition states of the reaction have not been clearly established yet. Here, we examined 12C/13C, 14N/15N and H2O/D2O isotope effects in Arabidopsis GS1 catalysis and compared to the prokaryotic (Escherichia coli) enzyme. A14N/15N isotope effect (15V/K ≈ 1.015, with respect to substrate NH4+) was observed in the prokaryotic enzyme, indicating that ammonium utilization (deprotonation and/or amidation) was partially rate-limiting. In the plant enzyme, the isotope effect was inverse (15V/K = 0.965), suggesting that the reaction intermediate is involved in an amidation-deamidation equilibrium favoring 15N. There was no 12C/13C kinetic isotope effect (13V/K = 1.000), suggesting that the amidation step of the catalytic cycle involves a transition state with minimal alteration of overall force constants at the C-5 carbon. Surprisingly, the solvent isotope effect was found to be inverse, that is, with a higher turn-over rate in heavy water (DV ≈ 0.5), showing that restructuration of the active site due to displacement of H2O by D2O facilitates the processing of intermediates.

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